These include transgenic mouse models overexpressing amyloid precursor protein (APP) or familial Alzheimer's disease (FAD) mutant APP (Salehi et al., 2006, Stokin et al., 2005), mutant presenilin-1 (Lazarov et al., 2007), and wild-type and frontotemporal dementia with parkinsonism (FTDP) mutant tau (Ishihara et al., 1999, Zhang et al., 2004). This evidence concerns the gene APP and semantic dementia.